Information Extraction And Feature Analysis Of Sediment Retention Dam In Loess Plateau Based On High Precision DEM

The Sediment retention dam is an important channel control project in Loess Plateau.It can conserve water and soil,stop flood and block sand,and build fields by silt,which plays a prominent role in soil and water conservation and comprehensive watershed management.However,some data of design may be missing after different stages of sediment retention dam construction.In the soil and water conservation practice,it is often faced with the problem of measuring the sediment volume.It is necessary to design a new method to estimate the volume of sediment because the traditional method has the disadvantages of low timeliness and high cost.At the same time,it is necessary to extract the siltation area and analyze its topographic variation characteristics.The emergence and development of modern spatial information technology,represented by remote sensing and GIS,has brought opportunities for related research.The main contents and conclusions of the paper are as follows.1.object-oriented image analysis(OBIA)method to quickly extract siltation areaBased on the data of digital elevation model,the rapid extraction of siltation area is realized by object-oriented image analysis method,and the extracted results are compared with the measured values in the statistical data.Verification results show a high degree of agreement,confirming the effectiveness and advantages of the OBIAbased siltation-area-extraction method.2.method of pre-siltation DEM restoration based on geometric modeling to estimate the volume of sedimentAccording to the law of geomorphological evolution of river basin,using the theory and method of digital terrain analysis,a kind of terrain restoration method of geometric shape simulation is designed to realize the restoration of DEM of study area before siltation.Lastly,t the volume of sediment is estimated by calculating the difference between the restored terrain grid and the present terrain grid.The effectiveness of the method was verified by comparison with the statistical data with high reliability.3.analysis of the features Change before and after construction of sediment retention damsBased on the principle and method of digital terrain analysis,the restored terrain is compared with the present terrain,and the corresponding index distribution map is made,and the statistical analysis is carried out.According to the results,the construction of sediment retention dams make the terrain of Wangmaogou basin lower and flat,Combined with the difference of LS factors,it proves the importance of construction of sediment retention dams.In this paper,through experiments such as the extraction of silt area and the restoration of watershed topography,the estimation of silt volume of silt dam is realized,and the change of topographic features before and after the construction of silt dam is comprehensively analyzed by using the theory and method of digital terrain analysis,which discusses the significance of sediment retention dams construction.